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about_blocks.rb
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about_blocks.rb
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require File.expand_path(File.dirname(__FILE__) + '/edgecase')
class AboutBlocks < EdgeCase::Koan
def test_calling_a_lambda
l = lambda {|a| a + 1}
assert_equal 100, l.call(99)
end
def test_calling_a_proc
p = Proc.new {|a| a + 1}
assert_equal 100, p.call(99)
end
def convert(&block)
block
end
def test_block_is_proc
b = convert {|a| a + 1}
assert_equal Proc, b.class
assert_equal 100, b.call(99)
end
def test_proc_takes_fewer_or_more_arguments
p = Proc.new {|a, b, c| a.to_i + b.to_i + c.to_i}
assert_equal 3 , p.call(1,2)
assert_equal 6, p.call(1,2,3,4)
end
def test_lambda_does_not_take_fewer_or_more_arguments
l = lambda {|a, b, c| a.to_i + b.to_i + c.to_i}
assert_raises(ArgumentError) do
l.call(1, 2)
end
assert_raises(ArgumentError) do
l.call(1,2,3,4)
end
end
def method(lambda_or_proc)
lambda_or_proc.call
:from_method
end
def test_return_inside_lambda_returns_from_the_lambda
l = lambda { return :from_lambda }
result = method(l)
assert_equal :from_method, result
end
def test_return_inside_proc_returns_from_the_context
p = Proc.new { return :from_proc }
result = method(p)
# The execution never reaches this line because Proc returns
# outside the test method
assert_equal __, p.call
end
end